The present invention concerns a lancet device for producing a puncture wound, in particular for collecting a sample of a body fluid. The lancet device has a magazine holder for a lancet magazine containing a plurality of lancets and can be alternatively operated such that either a new lancet is used for each puncture process by automatically advancing the lancet magazine stepwise or the automatic stepwise advance of the lancet magazine can be suppressed so that, if desired, several punctures can be carried out with the last used lancet before an unused lancet is used at a desired time.
The present invention additionally concerns a withdrawal system for withdrawing a sample of a body fluid comprising a lancet device as mentioned above and a matching lancet magazine containing several lancets.
Lancets which can be inserted into the appropriate body part to produce a puncture wound are usually used to withdraw a small amount of a body fluid such as e.g. blood from a suitable body part such as for example from a finger pad or earlobe for analytical or diagnostic purposes. Blood withdrawal systems which consist of a lancet device and appropriately adapted lancets suitable for such an application are well-known. Such lancet devices usually comprise a housing in which a lancet drive is located which moves the lancet mechanically for insertion into the selected skin area.
Nowadays, high demands are made on lancet devices with regard to producing a minimal pain sensation on the one hand, as well as simplicity in operation, compact design as well as cost-effective manufacture and economical operating costs on the other hand. The main focus is on a simple and comfortable operation of the lancet device which is especially important for diabetics who must frequently and regularly determine their blood sugar level by self-monitoring. In this connection, easy handling and low pain burden often result in a greater willingness of the patients to comply with this requirement and thus to support the success of the therapy.
An important advance in this regard is the use of lancets stored in a magazine i.e. lancets contained in a magazine. Such lancet magazines contain a plurality of lancets and can be inserted into the magazine holder of a corresponding lancet device. This makes it unnecessary to frequently insert or replace individual lancets which is a considerable facilitation in particular for diabetes patients with limited dexterity or eyesight. Accordingly, the demand for lancet devices with lancets stored in a magazine is increasing. The use of lancets stored in a magazine or lancet magazines in lancet devices usually requires a mechanism to advance or step the magazine forward which enables an unused lancet to be brought into use after a puncture process. However, it has turned out that even when using lancets stored in a magazine and the corresponding lancet devices it may also be desirable especially for economical reasons to use the stored lancet repeatedly if desired.
Accordingly, a lancet device is described in U.S. Pat. No. 8,002,785 which can hold a lancet magazine containing several lancets and which has a magazine advancing mechanism which enables the lancet magazine to be advanced in such a manner that the lancets stored therein can be successively coupled to a push rod of the lancet drive. The lancet drive is mechanically decoupled from the magazine advancing mechanism and the lancet device has an actuating element which allows the magazine advancing mechanism to be actuated independently of the lancet drive and in particular independently of the tensioning device. This enables the user to at any time exchange an already used lancet for an unused lancet by actuating the magazine advancing mechanism. However, a disadvantage of this system is that the magazine advancing mechanism in every case requires an active handling by the user which can result in an already used lancet being undesirably often used by forgetting to actuate the magazine advancing mechanism.
U.S. Publication No. 2006/0161078 A1 discloses a circular disk-shaped cassette for a test device as well as a test method using the said test device with the cassette. The cassette comprises a plurality of lancet needles as well as a plurality of test strips and a mechanism for linkage to the test device. Since each test element can only be used once, the cassette must be advanced stepwise either manually or automatically e.g. by means of an electric drive after a test process or puncture has been carried out.
Special lancing aids with a circular disk-shaped lancet magazine are also disclosed in U.S. Publication No. 2007/0299458 A1 where the lancets are each arranged radially facing outwards in the direction of puncture. The lancing aids have a mechanism which prevents intentional or accidental reuse of an already used lancet. This is achieved by means of the fact that in each tensioning process of the lancet drive the lancet magazine is rotated further such that a lancet that is as yet unused comes into contact with the lancet drive and additionally the replaceable lancet magazine has a lock to prevent the reinsertion of used magazines.
International Publication No. WO 2009/067269 A1 concerns a lancing aid with a replaceable circular disk-shaped magazine which comprises a plurality of lancets. The device has an anti-reverse mechanism so that the magazine can only be advanced in one direction thus preventing reuse of an already used lancet. Moreover, a mechanism is disclosed which enables one or more of the previously used lancets to be used again in an emergency. In order to preclude an accidental or improper use, the used up lancet magazine must if necessary be removed from the lancing device but in any case manually turned back against the actual direction of rotation.